Just been searching through some forums and after my post “How to find a Google Wave ID” I seem to have found a more simpler way to do it.
It really is as simple as 1, 2, 3
? Add mywaveid@appspot.com to your contact list
? Create a new wave and add mywaveid@appspot.com to the wave
? mywaveid@appspot.com will then display the wave ID like the screenshot below

Didn’t like the idea of Google Wave Bots, but they are really fantastic! There is a bot for just about anything!